Excellent new levels, solid new torture devices, and the thrill of supporting fascism.
If you’re a sadist who gets their jollies from killing orcs, then Artifacts of Power offers several fine new ways to express your fetish (and being on Steam, you just know you’ll be able to pick it up for small change during a sale!) and Lost Adventures adds a couple of new things to kill, and some wonderful arenas to kill them in.
Morally you could buy them when they’re under a dollar and almost escape the guilt of supporting DLC! Don’t let the fact that it’s an indie game fool you—you’re still supporting an evil regime.